Black Templar; Righteous Zeal

Does Righteous Zeal kick in once after every squad shoots at a unit and causes casualties, or once after the shooting phase is over. Example, if Squad A shoots BT unit 1 and kills 2, then squad B shoots at BT squad 1 and kills 1, then squad C shoots BT squad 1 killing 3. Would the BT unit get 3 RZ moves (1 after each squad shot) or would they get one after all enemy squads are done shooting at them?

Righteous zeal only kicks in at the point you pass the normal morale check for taking casualties (since if you fail, you run away).

Ok I worded my question poorly. Would you take 1 morale test per turn or would you take one test every time a unit suffers casualties. If its only 1 morale test per shooting phase (like losing 25% from shooting) then say 3 units caused wounds on the BT unit taking the test. Which unit would they RZ towards?